1. Field of the Invention
This invention is concerned with means for providing a gas oil composition at a reduced cost. More particularly the invention is concerned with a gas oil composition containing a major amount of cheaper higher boiling constituents and a minor amount of more expensive middle distillate, this fuel being a low pour composition owing to the incorporation therein of a small amount of an oil-soluble vinyl acetate-ethylene-vinyl chloride or allyl chloride terpolymer.
2. Description of the Prior Art
As is well known, gas oils distillates boiling at 650.degree.-750.degree. F. contain quantities of wax which render them viscous and give unacceptably high pour points. These oils behave as non-Newtonian liquids at low tempertures: exhibit variable solidifying temperature and peculiar hysteresis phenomena -- all of which render them difficult to use as fuel.
One approach used in converting these oils has been to subject them to fairly lengthy dewaxing procedures. This, however, is an expensive procedure.
Another approach which has been used to bring the viscosity of "crude" gas oils to suitable levels has been to dilute or "cut" them with a major amount of lighter distillate oils but this is an expensive procedure because of the considerably higher cost of the distillate oils relative to the higher boiling oils. Generally, the ratio of distillate to higher boiling gas oil used has been 9 to 1. The distillate can be sold directly as a diesel fuel and as such is valuable and in short supply.
A number of additives have been suggested and tried with success in lubricating oils and in so-called middle distillates in order to tie in the wax therein and improve fluid at low temperatures. Such additives consist either of compounds formed by alkylating benzene or naphthalene derivatives or of copolymers of ethylene-vinyl fatty acid ester of a molecular weight up to 3,000 and containing from 15 to 25% by weight of the vinyl fatty acid ester. These additives are not however, effective in depressing the pour point of crude turbine fuel oils.
It is therefore the main object of the present invention to provide a fuel composition based on crude oil which will be free of the above mentioned prior art limitations.
An equally important object of this invention is to provide a gas oil composition having improved pour point characteristics by incorporating therein a minor amount of distillate oil and a small amount of an oil-soluble vinyl acetate-ethylene-vinyl chloride terpolymer.
Other objects of this invention will in part be obvious and in part hereinafter pointed out.